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Purposeful construction versus self-assembly in approaches to single source precursors of spinel materials. Synthesis, structure and stability studies of MiiAl2(acac)3(OiPr)4(OAc), Mii= Mn, Co, Zn ? a new class of heterometallic heteroleptic alkoxide complexes

2004; Royal Society of Chemistry; Volume: 14; Issue: 21 Linguagem: Inglês

10.1039/b405771f

1364-5501

Gulaim A. Seisenbaeva, Evgeniya V. Suslova, M. Kritikos, Vadim G. Kessler, Laëtitia Rapenne, M. Andrieux, F. Chassagneux, Stéphane Parola,

Coordination Chemistry and Organometallics

The reaction of Mn(acac)3 with 3 eq. of Al(OiPr)3 in toluene at reflux provided with minor yield single crystals of MnAl2(acac)3(OiPr)4(OAc)(C7H8)0.5 (1), incorporating into the molecular structure the acetate ligand originating from oxidation of the OiPr-groups. 1 was obtained with high yield (76%) via the reaction of Mn(acac)3 with 2.2 eq. of Al(OiPr)3 with subsequent addition of 1 eq. of HOAc to the reaction mixture cooled to room temperature. The analogs of 1, CoAl2(acac)3(OiPr)4(OAc)(C7H8)0.5 (2), and ZnAl2(acac)3(OiPr)4(OAc)(C7H8)0.5 (3), were obtained with almost quantitative yields by reaction of the corresponding MII(acac)2 with 2 eq. of Al(OiPr)3 in toluene at reflux with subsequent addition of 1 eq. of Hacac and 1 eq. of HOAc after cooling the reaction mixture to the room temperature. In the molecules 1–3 the late transition metal atom is tetrahedrally coordinated (η2-acac plus 2 bonds to μ-OiPr-groups), and the Al atoms have a slightly distorted octahedral coordination (hexacoordinated) (η2-acac plus 3 bonds to μ-OiPr-groups plus one bond to μ-OAc-group). 1–3 are stable to solvolysis in toluene and are volatile under reduced pressure. Thermal decomposition of CoAl2(acac)3(OiPr)4(OAc)(C7H8)0.5 leads to nanoparticles of CoAl2O4, while homogeneous coatings of the spinel can be easily obtained using MOCVD.